Tubular steel towers for wind turbine installations are large in diameter and weight. Their size causes difficulties concerning the transportation of a tower to a wind farm. Usually, the steel towers for wind turbines are produced as sections in a shop and the sections are transported to the place of installation. The towers are typically constructed of a number of sections which have a cylindrical or conical shape.
In recent years larger turbines have been developed which require larger wind turbine towers. Consequently the diameters of tower sections have been increased and tower sections are becoming longer and heavier. The dimensions of tall towers for large wind turbines have reached limits defined by the infrastructure for transportation. The limiting aspects are typically physical limits such as free height under bridges and tunnels, allowable weights or the turning radii of roundabouts.
Various ways of connecting tower segments are known. In WO 02/077397 A1 a connecting flange has been disclosed for tower sections with a conical shape. The two connected flanges are fixed by bolts.
In US 2008/0308696 A1 a connection for wind turbine tower sections has been proposed, where each section is provided with flanges at its ends, the flanges are being connected by bolts and nuts.
From WO 2009/103475 an example for a connection between the bottom segment of the wind turbine tower to a foundation is known.
In EP 2 006 471 A1 a wind turbine tower has been proposed with sections with a polygonal cross-section, whereby each segment comprises a number of flat plates which form the polygonal cross-section.